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Fine‐tuning of phase behavior of oxazoline copolymer‐based organic–inorganic hybrids as solid‐supported sol–gel materials
Author(s) -
Gupta Surabhi,
Kataoka Tomoharu,
Watanabe Masao,
Ishikiriyama Mamoru,
Matsumi Noriyoshi
Publication year - 2019
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.48163
Subject(s) - lower critical solution temperature , copolymer , materials science , polymer chemistry , differential scanning calorimetry , polymer , endothermic process , chemical engineering , enthalpy , monomer , phase (matter) , chemistry , organic chemistry , thermodynamics , composite material , adsorption , physics , engineering
ABSTRACT Silica‐supported organic–inorganic polymer hybrids were synthesized via in situ sol–gel condensation of silica monomer in the presence of oxazoline copolymer. A stable copolymer of 2‐ethyl‐2‐oxaoline and 2‐isopropyl‐2‐oxazoline was prepared using methyl p‐tosylate as the living polymerization initiator with molecular mass of 4200 g mol −1 . Lower critical solution temperature (LCST) of this copolymer was thermally found to be at 77 °C. The copolymer was mixed with tetramethoxysilane (TMOS) in different amounts (0.039:1 to 0.158:1 weight ratios) via in situ sol–gel condensation to produce organic–inorganic hybrids including thermosensitive copolymer. Tuning of these solid‐supported materials showed sharp phase transitions changes in a temperature range from 42 to 58 °C, which was confirmed using differential scanning calorimetry. Enthalpy of the phase transition was also calculated using the area above the endothermic peak. A typical concave curve was obtained for LCST‐type phase diagram suggesting the dependence of phase transition temperature on the concentration of the copolymer in the hybrid. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48163.